Do you have the skills or an "IT Expert" friend who can try to place the drive into your computer? This is just to check that its the drive that has become corrupt and not your external unit controller card.

This is rare but at least you can verify that the external unit is not the cause of the issue

The other thing is to visit Western Digital and to download the Data Life Guard tools for your drive and run this to see if that can suggest anything.

Once you have the drive in a computer, you could also get your "IT Expert" to use a GNU/Linux LiveCD to create an image of the harddrive so that you could try to do repair options on this.

Example:

# Create image of the disk
dd if=/dev/sdd of=/some/place/WDImg.hdd
# Check the HDD partition
fdisk -l /some/place/WDImg.hdd
# If corrupt HDD partition try to repair using fdisk
fdisk /some/place/WDImg.hdd
# Now should have valid table
# attempt to mount the partition
# ensure you use correct fs type either vfat or NTFS
# also mount as ro just incase (even if we are only working on the image)
mount /some/place/WDImg.hdd /mount/here -t vfat -o ro
# you can now try to copy your data from this image to somewhere else
# try inserting a USB key to assist in this or mount another HDD as a
# temporary drive location

Hopefully you can fix the image enough to mount and extract your data. If these steps fail you may have lost your data.

The extra drive is bigger than my (internal) drive. I suppose I can try these commands on the hard itself, is that correct?
–
hasenJul 20 '09 at 1:56

I would not do it on the drive itself. See if you can borrow a drive from somebody of bigger or equal size to put the image onto
–
WayneJul 20 '09 at 2:08

Do this on the drive as a last method if you dont want to ship to a recovery place. Be aware that by doing it on the drive itself you could render the ability to recover the data worse than if you had left it at the state it is in now. You make that call tho :)
–
WayneJul 20 '09 at 2:08

If the data is marked as RAW, the data & filesystem itself is probably corrupt. You will need special tools to try and read the data.

Data Recovery Wizard will work for this, but it costs a fair bit. Just make sure you do not try and write anything to do the disk or reformat it. After it is written over once, you will lose your data.

Worst case scenario you will have to pay some data recovery experts to work their magic.

It does indeed sound like the file system has become corrupt. One thing I will mention here is there are some viruses that intentionally break external drive connections because you might find those very useful in removing the virus/malware. The one time a virus did that to me, it rendered the cd drive useless.

Spin rite probably won't work on this drive as it needs to be available at boot time. The poor man's option to data recovery is to buy an identical drive and swap the guts out yourself. This is a detail intensive process so you need to be ready for this. You will need some decent assembly/electronic skills, a soldering iron (if needed) and a home built HEPA enclosure to function as your clean room. I have always used a large box as my improvised clean room. Cut a window for your viewing portal, cut round holes and insert/tape dish-washing rubber gloves in the holes so that you can place your hands in the box without compromising the "clean room". Cover the inside of the box with foil, seal all edges and corners and then create a filtration port to attach your HEPA filter to.

If the partition table is screwed gpart (NOT gpartED) can recover your partition. The best program I've seen for FAT is GetDataBack, it's not free, but you can download their demo and see if it sees the files on the drive. Whether you're willing to spend $70 is up to you, but remember the software will come in useful next time this happens.

If that can't see it, you're going to have to look at file carving, and that's probably not something you're going to be able to do yourself...

External drive in a USB enclosure? USB fails more often than the drives do. Try another computer, then another enclosure. Finally, (or if no other enclosure available), put the drive in the computer, like everyone else suggests.

If you hear any type of clicking or screeching sound, then I'm sorry, you've lost your data. Your next option would be to send it off for recovery (could be up to $2k depending on the size of the drive).

-JFV

EDIT:
You can also put the external hard drive into your computer as a slave drive internally to have Windows run a chkdsk on it to see if it can repair any errors. This has (on occasion) worked for me as well. If it can be repaired via chkdsk, I would be prepared to back up the data immediately because the disk itself is failing.